Savings from senior discounts "really add up," says Barbara Rudder, a retiree from New York City, who pays half price for her weekly trips to New Jersey via public transportation and takes advantage of lower prices at many hotels, museums, and movie theaters.

Although cherished, senior discounts are under fire. Some critics wonder why older generations deserve a price break when younger generations are struggling more. There's also the question of affordability: Will businesses keep cutting prices for seniors as hordes of baby boomers push into their 60s?

"This is a huge influx of people," notes Margaret Lynn Duggar, a consultant in Tallahassee, Fla. "It's one thing if [senior discounts] apply to just 5 percent of the population, and another if you're talking about 35 percent."

Could senior-discounting go the way of the blue-plate special or dish night at the movie theater? "I can't imagine that five years from now any senior discounts will still be available," says Ken Dychtwald, founder of Age Wave, an Emeryville, Calif., consulting firm specializing in the mature market. "It's silly to give the most affluent segment of our society [an age-based] discount."

Senior discounts vary widely, with some offered as early as age 50. The size of the discounts also varies, with 10 percent about average. And they apply to a broad array of products and services, from groceries and property taxes to cellphone service and skydiving.

Many ski resorts let people ages 70 and older ski free of charge, says David Smidt, president of SeniorDiscounts.com, an online directory based in Albuquerque, N.M. "I even found a Cadillac dealer in Texas offering senior discounts."

More businesses appear to be offering them. For instance, SeniorDiscounts.com currently lists some 170,000 business locations with senior discounts, up from about 150,000 two years ago. More seniors are using them. AARP reports that 80 percent of all its members, who are 50 or older, say they have used a discount in the past 12 months.

Many baby boomers might sniff at discounts linked to old age, says David Weigelt, president and cofounder of Immersion Active, a Frederick, Md., firm specializing in Internet marketing to mature adults. But the stigma tends to fade as people get closer to qualifying for Social Security.

National companies like Southwest Airlines and Amtrak offer them, as do local firms like Dearborn Market, a food market and retail garden center in Holmdel Township, N.J. "We think the senior discount is a great thing to offer," says Nicole Luccarelli of Dearborn Market. "A couple of housing locations in the community provide small buses that take people to our store for the Tuesday discounts."

But criticism is popping up, especially as evidence mounts that younger people need a discount more than many seniors. In 2009, the median net worth of households headed by people 65 or older was 42 percent higher than the same-aged households in 1984, according to Pew Research, but households headed by those younger than 35 had 68 percent less wealth in 2009 than same-aged households 25 years earlier.

"A lot of people in the 50-to-70 age bracket are among the most affluent in the country," says Don Campbell, a semiretired journalist in Dayton, Ohio, who has written on the topic. "What is the logic in giving them a discount just because they've reached age 50, 55, or 67?"

In the end, the future of senior discounts may depend on the reasons for offering them, says Mark Doherty, vice president at Chadwick Martin Bailey, a Boston-based market research and consulting firm. "If these discounts have been offered as a charity or public service, it's more likely than not they'll go away" as more boomers qualify for the profit-eating discounts. "But if discounting is an investment to attract the boomers and start a relationship with them, I think it will continue or expand."